Electrotherapy is the use of electrophysical agents for both evaluation and treatment in a broader context today. The terms “Electrotherapy” and “Electrophysical Agents” are interchangeable terms in the use of any of the electrophysical agents applied externally to the human body for evaluation and treatment. The electrotherapy has been used for many years in physiotherapy and rehabilitation science. The recent growth in the use of electrotherapy is probably related to recent manufacturing improvements in electrotherapy devices that make the use of these devices more easier and make the use of enhanced treatment options possible.
Characteristics of the Currents
Electric currents create electrothermal, electrochemical, and electrophysical effects in the body in order to achieve therapeutic purposes by revealing direct and indirect physiological responses in the tissues. It is important that practitioners have a good understanding in the basics of electrotherapy and have the ability to apply these basics in order to achieve the desired outcomes.
The desired effects and outcomes of electrotherapy can be influenced specifically by the current type, intensity, voltage, duration, and density of the electrical current. The characteristics and type of the involved or targeted tissue will also affect the outcome of electrotherapy.
Current type: The commonly used electrical currents are direct (DC), alternating (AC), and pulsatile (PC). The current type differentiates depending on:
- Waveform: sinusoidal, rectangular, twin spike
- Amplitude: current intensity
- Pulse duration: width or one pulse length time, a shorter duration is more comfortable
- Frequency: rate or number of pulses or cycles delivered in per unit time; pulse per second (pps) for PC, or cycles per seconds (cps) for AC. Low-frequency currents used to provide analgesia and to stimulate motion. Medium-frequency currents employed chiefly for pain control. High-frequency currents used to cause a thermal, analgesic and anti-inflammatory effect.
- Polarity: Polar or apolar stimulation
Action Mechanism of Electrotherapy
Changes occur at various levels of body systems with electrical currents. These changes occur at 4 levels: cellular, tissue, segmental, and systemic. Many structures at any level are affected by means of increased or suppressed physiological activities directly, indirectly, or both.
Table 1. The Physiological Effects of Electrotherapy
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D: Direct effects, ID: Indirect Effects
Therapeutic Goals of Electrotherapy
Muscle reeducation: Retrain firing patterns or overcome neuromuscular inhibition in intact muscles following injury or pathology. The mechanism is thought in order to increase the quantity of recruited motor units or in order to decrease the inhibition of the motor nerves that limits normal function.
- Retard atrophy: Cause the muscle to contract during an effort in order to reduce the effects of immobilization or paralysis on atrophy.
- Retard edema formation: Limits the formation of edema during acute inflammation by inhibiting the increase in vascular permeability with sensory-level stimulation.
- Remove edema: Removing existing edema through a muscle pump mechanism with motor-level stimulation.
- Reduce pain: Interfere with the transmission or perception of pain through a variety of different electrotherapy approaches.
- Reduce spasm: Reduce acute spasms by either decreasing the muscle's contraction frequency or by fatiguing the muscle up to failure (very uncomfortable). Electrotherapy can also be used in order to manage the spasticity associated with neuromuscular diseases or spinal cord trauma.
- Increase strength: Increase muscle force output in nonpathologic tissue by causing hypertrophy of the muscle. Although the muscular strength can be improved with motor-level stimulation, the required protocols are very uncomfortable and are not nearly as effective as resistance exercise. This is not generally an appropriate goal for electrotherapy.
- Increase range of motion: A commonly cited but misleading goal. Electrotherapy can be effective in reducing muscle spasticity or edema , which can be encountered with the associated loss of ROM . Improving ROM by itself is not an effective aim of electrotherapy.
- Transport medications: Iontophoresis deliver medications by driving electrically charged ions through the skin.
- Tissue healing: There are some evidences that microcurrent may augment tissue repair in individuals with fractures or slow-healing skin ulcerations. The mechanism has yet to be described.
Electrotherapy Modalities
- Iontophoresis
- Faradic Current
- Diadynamic Currents
- High Voltage Pulsed Current
- Transcutaneous Electrical Nerve Stimulation (TENS)
- Microcurrent Therapy
- Interferential Therapy
- Russian Stimulation
- Shortwave Therapy
- Microwave Therapy
- Therapeutic Ultrasound
- Magnetic Therapy
- Shockwave Therapy